1. Field of the Invention
The present invention relates to golf shoes, and more particularly to an improvement in a pattern of a bottom surface of golf shoes.
2. Description of the Related Art
When hitting a golf ball, a golf player sets an address such that a line connecting right and left tiptoes are in almost parallel with a hitting direction. In an address for a right-handed golf player, a left foot is positioned on the front side in the hitting direction and a right foot is positioned on the rear side in the hitting direction. In the address, a head of a golf club is positioned close to a golf ball. In this state, the golf player starts take-back, pulls the head rearward and then swings the golf club upward. The highest position of the head swung upward is equivalent to a top position. In the top position, a down swing is started and the head is swung downward so that the head impacts the golf ball. After the impact, the golf player swings the golf club forward and then upward (follow-through). Thus, a finish is attained.
From the top position to the finish, the golf player carries out a body turn by setting a left foot as a pivot. At the same time, the golf player kicks the ground by a right foot to transmit the force to the golf ball. In other words, a right-handed golf player uses a left foot as a pivoting foot and a right foot as a kicking foot. To the contrary, a left-handed golf player uses a right foot as the pivoting foot and a left foot as the kicking foot.
From the top position to the finish, great force is applied to both feet of the golf player. In some cases, the force causes golf shoes to slip off from the ground. In some cases in which the slip is caused, a swing form is disordered so that a misshot is generated.
In order to attain slip prevention, a needle-like spike pin formed of metal or ceramics is provided on the bottom surfaces of the golf shoes in some cases. In such golf shoes, the slip is considerably prevented. However, there is a problem in that the spike pin damages a lawn on a green, a floor in a clubhouse and a road surface of a passage for walking which is provided in a golf course. Moreover, the golf shoes having the spike pin give a push-up feeling and are not comfortable for the golf player to wear. In recent years, the golf shoes having the spike pin have not been preferred for use.
Golf shoes having a projection formed of rubber or synthetic resin which are provided on bottom surfaces in place of the spike pin have been proposed and spread. Such golf shoes rarely damage a lawn and are very comfortable to wear. In the golf shoes, however, there is a problem in that the projection has a smaller slip prevention performance than the spike pin. Japanese Patent No. 2946215 has proposed golf shoes in which a shoe for a left foot and a shoe for a right foot have different projection patterns in consideration of a difference in a role between the left and right feet. In respect of an enhancement in the slip prevention performance, however, the golf shoes still leave room for an improvement.
The present inventor investigated a vector of force applied to feet from the top position to the impact (that is, a magnitude and a direction) and found the following.
For a pivoting foot, force is roughly applied in almost a direction from a heel to a toe. In detail, the force is mainly applied to a rear portion in the hitting direction of the foot in the top position (toward an inside for the pivoting foot of the golf player) and the direction is also equivalent to a slightly rearward toe direction. Depending on the progress of a swing, the position to which the force is mainly applied is transferred to the center of the foot, and then a front portion (toward an outside for the pivoting foot of the golf player). Depending on the progress of the swing, moreover, the direction of the force is also transferred in a complete toe direction, and then in a slightly forward toe direction. It is supposed that these changes are caused by a body turn using a pivoting foot as a pivot and the movement of a weight.
For a kicking foot, force is roughly applied in almost a direction from the toe to the heel. In detail, the force is mainly applied to a front portion in the hitting direction of the foot in the top position (toward an inside for the kicking foot of the golf player) and the direction is also equivalent to a slightly forward heel direction. Depending on the progress of a swing, the position to which the force is mainly applied is transferred to the center of the foot, and then a rear portion (toward an outside for the kicking foot of the golf player). Depending on the progress of the swing, moreover, the direction of the force is also transferred in a complete heel direction, and then in a slightly rearward heel direction. It is supposed that these changes are caused by movement of a weight from the kicking foot to the pivoting foot at the time of the start of a downswing and the subsequent rotation of the kicking foot.
Based on these knowledges, the present inventor has proposed golf shoes in Japanese Patent Application No. 2000-123756 in which a pattern of a projection is varied in right and left shoes. In the golf shoes, a projection is formed along a convex line in a direction of a toe over a bottom surface of a shoe for a pivoting foot and a projection is formed along a convex line in a direction of a heel over a bottom surface of a shoe for a kicking foot. In a golf swing having such a very complicated movement pattern having a turning movement (body turn) and a translation movement, the golf shoes display an excellent slip prevention performance.
However, in the case in which the slip prevention is achieved by the projection having different patters on left and right, it is necessary to prepare both the golf shoes for a right-handed golf player and a left-handed golf player and the burden of a cost is increased for golf shoes manufactures. Moreover, if the left-handed golf player wears golf shoes for the right-handed golf player or the right-handed golf player wears golf shoes for the left handed golf player, there is a problem in that the slip prevention is insufficient during a swing. Furthermore, there is also a problem in that a shoe for a pivoting foot and a shoe for a kicking foot in the golf shoes easily slip on upward and downward slopes respectively.
The present invention has been made based on these knowledges and has an object to provide golf shoes for preventing a slip during a golf swing in the case in which any of the right-handed and left-handed golf players wears the golf shoes.
In order to achieve the above-mentioned object, the present invention provides golf shoes comprising an outsole body and a large number of projections formed of rubber or synthetic resin which are provided on a bottom surface of the outsole body, wherein both side slip prevention projections including a toe side slip prevention wall formed along a convex line in a direction of a toe and a heel side slip prevention wall formed along a convex line in a direction of a heel are mainly formed.
The golf shoes comprise the both side slip prevention projections. Also in the case in which any of the right-handed and left-handed golf players wears the golf shoes, a slip of a pivoting foot (a slip in almost a direction of a toe) and a slip of a kicking foot (a slip in almost a direction of a heel) can be prevented during a golf swing.
It is preferable that a ratio of the number of the both side slip prevention projections to the total number of the projections should be 50% or more. Consequently, it is possible to more prevent the slip during the golf swing.
It is preferable that an interior angle on a vertical section which is formed by the toe side slip prevention wall and the outsole body should be 60 degrees or more. Moreover, an interior angle on a vertical section which is formed by the heel side slip prevention wall and the outsole body is also 60 degrees or more. Consequently, it is possible to more prevent the slip during the golf swing.